Hose guide for rock drills



April 28, 1970 M. C. HUFFMAN HOSE GUIDE FOR ROCK DRILLS Filed Aug. 13,1968 c J o I 4| O4 a 2 Sheets-Sheet 1 //vl /vTOR Merv/n C Huffman AGE/VTApril 28, 1970 M. c, HUFFMAN 3,508,619

HOSE GUIDE FOR ROCK DRILLS Filed Aug. 13, 1968 2 Sheets-Shzgt 2 UnitedStates Patent US. Cl. 173-147 14 Claims ABSTRACT OF THE DISCLOSURE Aguide and positioning mechanism for the motive fluid hoses of a mastmounted rock drill comprising a hose reel and frame assembly slidablymounted on the drill mast and driven along the mast at a predeterminedspeed relative to the drill by a transmission unit. The transmissionunit includes two shaft and sprocket assemblies rotatably mounted on theframe with each of the shafts having a sprocket engaged with one of theoppositely moving strands of an endless drill feed chain. The respectivetransmission shafts also mount two speed reduction sprockets ofdifferent diameters which are connected by a second endless chain. Apredeterminable diameter ratio between the speed reduction sprocketsprovides for driving the reel and frame along the mast at any selectedspeed relative to the drill.

BACKGROUND OF THE INVENTION Conventional percussion rock drills requirea plurality of flexible fluid conductors leading from a source ofpressure fluid via a bank of control valves to the drill proper forconducting the motive fluid to the drill percussion motor and forproviding hole cleansing fluid. Some types of drills also requireadditional fluid conductors for drill steel rotation motors. For drillsWhich are mounted on masts or guide shells it is desirable to providefor positioning or guiding the elongated fluid conductors or hoses undermoderate tension to prevent them from becoming entangled, kinked, orotherwise damaged as the drill is fed back and forth along the mastduring normal operation.

An example of a flexible fluid conductor guide and positioning mechanismin the prior art is disclosed in US. Patent 3,162,253 to J. C. Curtis.The Curtis patent discloses a hose reel mounted on the drill mast of aconventional rock drilling mechanism of the type which comprises anendless chain for feeding the drill along the mast. In the arrangementof Curtis the flexible hoses are looped over a reel or sheave which inorder to provide for proper tension on the hoses is required to beadvanced along the mast at one half the speed of the drill. In order toobtain the desired speed ratio between the drill and hose reel, theCurtis device requires separate endless drive chains extendingsubstantially the entire length of the mast and journaled on separatesprocket assemblies of diameters selected to provide for the properrelative linear velocity of the hose reel and drill. Other devices knownin the prior art include cable and drum assemblies which requireseparate drive means for advancing and retracting the hose reel.Generally, known mechanisms, inclusive of the types mentioned above, areunduly complicated mechanically and therefore require additionalmaintenance of the drilling equipment as well as adding substantialweight and bulk to the drill support structure.

SUMMARY OF THE INVENTION The present invention resides in an improvedhose positioning and tensioning mechanism comprising a grooved reelslidably mounted on a guide shell or mast of a P CC drilling apparatus,the reel being drivably connected to a transmission means engaged by andmovable with an endless drill feed chain. The invention further providesfor a reel transporting means which is advantageously connected solelyto a conventional drill feed chain. The positioning reel drivetransmission provides for feeding the reel in the direction of thestrand of the drill feed chain to which the drill is attached but at avelocity less than the drill itself.

A particularly advantageous aspect of the invention resides in theprovision of a transmission having a speed reduction means comprising aflexible endless drive element engaged with a pair of speed reductionwheels of differential diameter whereby a predetermined velocity of thetransmission relative to a flexible endless feed means is achieved.

A specific object of the present invention is the provision of a drivetransmission for a conductor positioning reel which is operable directlyfrom an endless drill feed chain to drive the reel at a velocity equalto one half the feed rate of the drill to which the conductors areattached.

Another advantageous aspect of the present invention is the compact andsimplified construction of the reel drive transmission which isdesirably housed within the normal cross section envelope of a drillmast. The transmission thereby is protected from possible damage fromfalling rock and debris, and furthermore does not add additional bulk tothe mast and associated structure. Reliability and maintainability ofthe drill structure is enhanced by the compact and easily accessiblemechanism. Further advantages and objectives realized with the presentinvention will be better understood upon reading the detaileddescription below.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal side view,partially sectioned, of a drill mast and feed chain assembly.

FIG. 1a is a continuation of FIG. 1 from the line aa illustrating theremainder of the drill mast and feed chain assembly including the drilland the hose positioning and tensioning mechanism.

FIG. 2 is a section view taken along the line 2-2 of FIG. 1a.

FIG. 3 is a section view taken along the line 33 of FIG. 1a.

FIG. 4 is a schematic representation of the feed chain and thetransmission of the hose positioning and tensioning mechanism includingrepresentative velocity vectors of the respective components in theforward feed condition.

FIG. 5 is a front elevation of a crawler mounted rock drilling machineillustrating the flexible motive fluid hoses trained over thepositioning and tensioning reel.

DESCRIPTIONOF THE PREFERRED EMBODIMENTS 10. The mast assembly 10comprises inwardly facing elongated channel members 12 and 14 joined byintermediate members such as at 16 and 18 (FIGS. 2 and 3) to form arigid support for slidably mounting a fluid operated percussion drillmotor 20 ona slide 22. The lower end of the mast assembly 10 includes abracket 24 for mounting a stabilizing plate 26 and for supporting adrill steel centralizer 28 for guiding the extension drill steel 30. The

mast assembly 10 also includes a mounting cone 32 which cooperativelymounts on a positioner and boom assembly, not shown, of any of a numberoftypes well known in the art of adjustable drill mountings.

The lower end of the mast assembly shown in FIG. 1 also mounts apressure fluid feed motor 34 and gear drive 36 having a rotary outputmeans comprising a sprocket 38 drivably engaged with endless flexibledrill feed means comprising a chain 40 which extends virtually theentire length of the mast assembly 10. The feed chain 40 has oppositelymoving strands 41 and 42 supported at the lower end over a sprocket 43and an idler sprocket 44, and at the upper end over an adjustablymounted sprocket 46 which is in turn rotatably supported by a chainadjustment block 48. The feed chain 40 lies in a plane essentially alongthe longitudinal centerline of the boxlike structure formed by thechannel members 12 and 14, and is secured to the drill mounting slide 22by a clamp 50, FIG. la, whereby the drill 20 is conveyed or fed alongthe mast assembly 10 at the same velocity as the strand 41.

Situated at the extreme upper end of the mast assembly 10 in theposition illustrated in FIG. 1a is a grooved reel 52 rotatably mountedon a hub 54 which is secured to a frame 56. The frame 56 comprises aplate 58 (FIGS. 2 and 3) having grooves 60 and 62 slida'bly engageablewith the flanged portions 64 and 66 of the channel members 12 and 14,respectively. The frame 56 also includes parallel bearing support plates68 and 70 for a hose reel drive transmission generally designated by thenumeral 72. The reel 52 forms positioning means for a plurality offlexible conductors comprising pressure fluid rotation motor hoses 74and 76, a drill motor supply hose 78, and a drill hole cleansing fluidhose 80. The hoses 74, 76, 78 and 80 extend from a series of respectiveconnectors 82, 84, 86 and 88 which are rigidly secured to the mastassembly 10 near its longitudinal midpoint (FIG. 1) by a bracket 90 andclamps 92 and 94. The flexible hoses are trained over the reel 52 whencethey lead to the backhead 96 of the percussion drill motor 20 as may beseen in FIG. 5.

The hose reel 52 is desirably fed along the mast assembly 10 at apredetermined velocity less than the feed rate of the drill motor 20.For reasons to be explained later herein, the desired feed rate of thehose reel 52 is substantially one half the rate of travel or velocity ofthe strand 41 of the chain 40. This predetermined velocity of the hosereel 52 and supporting frame 56 is provided by the transmission 72mounted on the frame 56 and engaged with both the strand 41 and thestrand 42 of the feed chain 40.

Referring to FIG. la, FIG. 2 and FIG. 3 the transmission 72 includes afirst shaft means 98 rotatively supported on bearings 100 and 102 housedin the respective bearing plates 68 and 70. The shaft 98 has integrallyformed thereon a first drive wheel means comprising a toothed sprocket104 engaged with the strand 42 of the chain 40. Also integral with theshaft 98 is a speed reduction wheel or sprocket 106 which is drivablyinterconnected with a second speed reduction sprocket 108 mounted on asecond shaft means 110 by means comprising a chain 112. The shaft 110 isrotatively journaled parallel to shaft 98 in bearings 114 and 116mounted in the plates 68 and 70. The shaft 110 additionally includes thedrive sprocket 118 engaged with the strand 41 of the chain 40. Thesprockets 106 and 108 are of predetermined differential diameters andthe sprockets 104 and 118 are of equal diameter. The effective diameterfor the determination of linear velocities for chain sprockets will beunderstood to be the pitch diameter of the sprock ets which will bereferred to in determining velocity ratios rather than the number ofteeth in respective sprockets.

An important consideration in the kinematics of chain drives is that thecenterline of a chain is not at a uniform radius as the chain passesaround the sprocket. This is particularly true for sprockets havingsmall numbers of teeth. However, the variation in linear velocitydecreases as the number of teeth increases and for ractical ap licationswherein minute variations are of no consequence, sprocket pitch diametercan be used for calculation of velocity ratios. Furthermore, it will beapparent to one of ordinary skill in mechanics of machinery that thechain and sprocket arrangement could be replaced by a variety ofequivalent elements, for example, a toothed belt and cog wheelarrangement or a friction drive comprising belts and pulleys.

As previously mentioned the hose reel 52 is desirably fed along the mast10 at a velocity less than the drill 20. Therefore, since the drill 20is secured to the strand 41 of the chain 40 the velocity of the drillwith respect to the mast 10 is equal to the velocity of the strand 41with respect to the mast 10. However, the hose reel 52 and transmission72 should travel with respect to the mast at one half the velocity ofthe drill. Such rate of travel of the reel 52 is accomplished byselecting the diameter of the sprocket 108 to be three times thediameter of the sprocket 106. An analysis of the respective velocitiesof the transmission components will verify such a choice of diameterratio of the sprockets 108 and 106.

Referring to FIG. 4, angular velocities are denoted W and linearvelocities V for the respective components of the transmission 72 shownschematically. For mathematical purposes counterclockwise angularvelocities are positive and the direction of the velocity vector ofstrand 41 is positive. In the equations below subscript numerals are thereference characters of the respective components, and single subscriptsdenote velocities with respect to the mast assembly 10.

The angular velocities of sprockets 104 and 106 are equal since they arerigidly secured to shaft 98. The same relationship is true for sprockets108 and 118 on shaft 110. However, sprocket 106 is connected to sprocket108 by chain 112 therefore Sprockets 104 and 118 are fixed to frame 56by means of bearing plates 68 and 70, therefore and chain 40 is endless,so

42= 41 (vi) Furthermore 11s 41= 11a 11a (vii) where r is the pitchradius of sprocket 118 (one half the pitch diameter) and As previouslystated the diameters of sprockets 118 and 104 are equal, therefore 13yproper substitution of the above stated relationships 1nto Equation v inaccordance with the algebraic sign convention of FIG. 4 the velocity ofthe transmission 72 may be expressed in terms of the velocity of strand41 of the chain 40.

N-l-l (x) Therefore it can be seen that for a diameter ratio of thesprocket 108 to the sprocket 106 of N =3 the velocity of thetransmission 72 and the attached hose reel 52 is one half the velocityof strand 41 with respect to the mast 10 and also therefore with respectto the drill 20.

It will be apparent to one skilled in the art in view of the foregoingdisclosure that various diameter ratios of the sprocket 108 to thesprocket 106 or their equivalents could be employed in a transmissionsuch as the embodiment shown and designated by the numeral 72 to give anextensive range of velocities of the transmission and attached structurerelative to an endless conveyor means.

FIG. illustrates the mast assembly mounted on a crawler typeundercarriage 120 in a vertical drilling position. Pressure fluid e.g.compressed air is supplied from a source, not shown, via a line oiler122 and a main supply hose 124 to a control valve manifold 126 having aplurality of valves 127 providing for control of the drill feed,rotation, drill motor power, and hole cleansing fluid by an operator.The plural flexible conductor hoses can be partially seen in FIG. 5leading from the manifold 126 to the intermediate connectors and clampassembly and over the reel 52 to the drill motor backhead 96.

The hoses 74, 76, 78 and 80, FIG. 1a, are initially drawn moderatelytaut, so that they do not drag along the mast 10 when the latter is inthe horizontal position, by positioning the drill motor 20 and the hosereel 52 at the extreme upper end of the mast assembly 10 as shown. Thedrill motor is then secured to the strand 41 of the chain by the clamp50 and the hoses are adjusted for the desired tightness at the clamps 92and 94, FIG. 1.

In typical operation as depicted in FIG. 5 as the drill motor 20 is fedalong the mast 10 the reel 52 is fed at one half the speed of drill bythe transmission unit 72. Due to the looped arrangement of the hoses 74,76, 78 and 80 over the reel 52 they pay out off the reel at the samevelocity as the drill 20 even though the reel is traveling at one halfspeed relative to the drill proper. When the feed motor 34 is reversedto retract the drill 20 and extension drill steel 30 from the hole, thereel 52 is also driven in the reverse direction, again at one half speedrelative to the drill 20, to maintain the predetermined tension in thehoses 74, 76, 78 and 80.

What is claimed is:

1. In a drilling apparatus:

elongated drill support means;

drilLmotor means mounted on and linearly movable with respect to saidsupport means;

feed means mounted on said support means and connected to said drillmotor means for feeding said drill motor means reversibly along saidsupport means; flexible conductor means having one end connected to saiddrill motor means and having another portion connected with respect tosaid support means;

the improvement comprising: positioning means linearly movable withrespect to said support means for positioning said flexible conductormeans with respect to said drill motor means, said positioning meansincluding a transmission having at least one wheel means engaged withand rotatably driven by said feed means, said wheel means being linearlymovable with respect to said sup-port means in the same direction assaid drill motor means and in response to the operation of said feedmeans whereby said positioning means is moved with respect to saidsupport means at a linear velocity less than said drill motor means.

2. The invention according to claim 1 wherein:

said feed means comprises endless flexible means forming two oppositelymoving strands extending substantially the length of said support means,and said transmission means includes wheel means operatively engagedwith both of said strands for driving said positioning means in the samedirection as one of said strands at a predetermined linear velocity lessthan the linear velocity of said strand.

3. The invention according to claim 2 wherein:

said drill means is secured to one of said strands and is movabletherewith along said support means, and said positioning means is drivenalong said support means at a predetermined linear velocity less thansaid drill means.

4. The invention according to claim 2 wherein:

said positioning means for said conductor means comprises a framesupporting said transmission means, first and second shaft means mountedon said frame; first drive wheel means on said first shaft means andengaged with one of said strands, second drive wheel means on saidsecond shaft and engaged with said oppositely moving strand, and speedre duction means interconnecting said first and second drive wheel meansoperable to provide for driving said positioning means in the directionof one of said strands at a linear velocity less than said strand.

5. The invention according to claim 4 wherein:

said speed reduction means comprises first speed reduction wheel meansmounted on said first shaft in nonrotatable relationship relative tosaid first drive wheel means, second speed reduction wheel means mountedon said second shaft in nonrotatable relationship relative to saidsecond drive wheel, and means drivably interconnecting said first andsecond speed reduction wheel means.

6. The invention according to claim 5 wherein:

said first and second speed reduction wheels are of different diameterand said interconnecting means provides for driving said first drivewheel means at an angular velocity greater than said second drive wheelmeans in the ratio of the diameter of said second speed reduction wheelto the diameter of said first speed reduction wheel.

7. The invention according to claim 6 wherein:

said means drivably interconnecting said first and second speedreduction wheels comprises endless flexible means.

8. The invention according to claim 7 wherein:

said endless flexible means interconnecting said first and second speedreduction wheels comprises a chain and said speed reduction wheelscomprise sprockets drivably engaged with said chain.

9. The invention according to claim 4 wherein:

the diameters of said first and second drive wheel means are equal.

10. The invention according to claim 4 wherein:

said endless flexible feed means com-prises a chain and said first andsecond drive wheel means comprise sprockets drivably engaged with saidchain.

11. The invention according to claim 6 wherein:

the velocity of said positioning means with respect to said drillsupport means Vg can be expressed:

where V is the velocity of said strand to which said drill motor issecured with respect to the drill support means and N is the ratio ofthe diameters of said second speed reduction wheel to said first speedreduction wheel.

12. The invention according to claim 11 wherein: the value of N equalsthree.

13. Transmission means operable to be linearly driven along the path ofan endless flexible conveyor having two oppositely moving strands, saidtransmission means to be driven in the direction of movement of one ofsaid strands at a linear velocity less than the velocity of said one ofsaid strand, and said transmission means being drivably engaged withboth of said strands of said conveyor.

7 8 14. The invention according to claim 13 wherein: of one of saidstrands at a velocity less than the said transmission means comprises:velocity of said strand.

aframe; first drive wheel means rotatively mounted on said ReferencesCited frame, and engaged with one of sald strands of 5 UNITED STATESPATENTS sa1d conveyor means,

2,730,332 l/1956 Hale l73--l47 second drive wheel means rotativelymounting on said frame, and gaged with said oppositely moving 6 t f d da a u 15 s rando Sal conveyor means an 3,205,951 9/1965 Pyles 173 .16Q

speed reduction means operatively connected to 10 said first and seconddrive Wheel means whereby in response to said strands of said conveyormeans JAMES LEPPINK Primary Exammer moving in opposite directions at agiven velocity US. Cl. X.R. said speed reduction means operates toprovide for l73160 moving said transmission means in the direction 15

